Fiberglass grating formed of interlocked pultruded fiberglass grating bars

Abstract

A fiberglass reinforced molded resin grating is formed of first and second sets of mutually parallel, interlocking fiberglass reinforced molded resin bars with the sets extending transversely to one another. One set consists of bearing bars of rectangular cross section including at longitudinally spaced positions within an upper edge, inverted U-shaped notches including oppositely directed, downwardly and outwardly oblique slots terminating at their upper ends adjacent the upper edge of the bearing bars in upwardly and outwardly diverging oblique cam surfaces. The second set of bars consist of cross bars of inverted U-shaped cross section including a horizontal base portion and a pair of downwardly and outwardly diverging legs of a thickness equal to the width of the diverging slots and being respectively received in said slots. The legs of the cross bars at longitudinally spaced position are provided with rectangular locking notches from the free ends upwardly of a width generally equal to the thickness of the bearing bars and of a height which is less than the vertical height of the cross bars. The cross bars are forced downwardly at the locking notches into the inverted U-shaped notches formed within the upper edge of the bearing bars with the cam surfaces deflecting the oblique legs of the cross bar to momentarily deform the legs to cause the portions of the legs at the locking notches to snap into the oblique slots of the inverted U-shaped notches within the bearing bars to mechanically interlock the first and second sets of the bars together.

What is claimed is: 
     
       1. A fiberglass reinforced molded resin grating comprising: first and second sets of mutually parallel, interlocking fiberglass reinforced molded resin bars, which sets extend transversely to one another;   said first set of bars comprising underlying bearing bars of rectangular cross section having opposite sides and upper and lower edges, being of a thickness T and having a height H, each bearing bar, including at longitudinally spaced positions within said upper edge, inverted U-shaped notches of vertical depth D including oppositely directed, downwardly and outwardly oblique slots, said oblique slots terminating adjacent the upper edge of said bearing bar in outwardly and upwardly diverging, oblique cam surfaces which are spaced apart at said top edge by a distance W", said second self interlocking fiberglass reinforced molded bars constituting cross bars, being of inverted U-shaped cross section including integrally, a horizontal base portion and a pair of downwardly and outwardly diverging legs of a thickness equal to the width of the diverging slots of the inverted U-shaped notches within said bearing bars and being of a vertical height H', in excess of the vertical depth D of said inverted U-shaped notches within said bearing bars, said cross bars having a flat horizontal upper edge, and oblique outwardly diverging sides, said cross bars including, at longitudinally spaced positions, rectangular locking notches within respective legs and being of a width W' which is generally equal to the thickness T of the bearing bar and of a height H' which is less than the vertical height H" of said cross bars, said locking notches forming laterally opposed vertical edges which contact the opposite sides of the bearing bars and forming horizontal edges for said rectangular locking notches within the legs of the cross bars, which horizontal edges, are spaced from each other by a distance S on opposite sides of said cross bars which is less than the distance W" between the upper edges of the oppositely oblique camming surfaces at the upper ends of the oppositely oblique slots of the inverted U-shaped notches within the bearing bars, whereby; the portion of the cross bar legs above the locking notches are deflected inwardly during forced insertion of the cross bars at the locking notches into the inverted U-shaped notches of the bearing bars by camming action of the camming surfaces at the upper end of the oblique slots to momentarily deform the cross bar legs to permit entry thereof into the inverted U-shaped notch slots of the bearing bars whereupon, said cross bar is joined to the bearing bars with the oblique legs of the cross bars snapping flush with oblique surfaces of the downwardly and outwardly oblique slots within the bearing bars thereby preventing removal of the cross bars from the bearing bar inverted U-shaped notches by frictional surface contact and resilient pressure between the oblique legs of the cross bars and the slots within the bearing bars, after completion of assembly of the grating.   
     
     
       2. The fiberglass reinforced molded resin grating as claimed in claim 1 wherein the vertical height of the locking notches within the legs of the cross bars are dimensioned relative to the overall height of the cross bar and the depth of the inverted U-shaped notches within the bearing bars such that the upper edges of the cross bars and bearing bars are flush upon completion of the mechanical interlock between the cross bars and bearing bars at said locking notches.